Molded plastic fastener having a sheet metal core element



A ril 16, 1963 B. G. FORMAN 3,035,451

MOLDED PLASTIC FASTENER HAVING A SHEET METAL CORE ELEMENT Filed Aug. 1, 1960 United States Patent Illinois Filed Aug. 1, 196%), Ser. No. 46,541 1 Claim. (or. s-r

This invention relates generally to the field of metallic reinforced synthetic resinous screws, bolts and the like, and more particularly to an improved type having an insert molded reinforcement.

It is among the principal objects of the present invention to provide a sheet metal insert for use in conjunction with such devices which may be formed integrally with a plurality of other similar inserts in such manner that the interconnected devices may be simultaneously inserted into a multi-cavity mold whereby a plurality of fasteners may be simultaneously formed, following which the integrated fasteners may be removed from the mold and readily separated.

A further object of the invention lies in the provision of an improved metallic core element which may be formed from sheet metal stock using progressive extruding metal dies.

Still another object of the invention lies in the provision of an improved method for forming metal reinforced synthetic resinous fasteners requiring fewer manual operations than has heretofore been the case.

A further object of the invention lies in the provision of a sheet metal insert molded synthetic resinous fastener in which the cost of fabrication is materially reduced as contrasted with prior art devices, with consequent Wide sale, distribution and use.

A feature of the invention lies in the very high mechanical strength obtained using the novel core structure disclosed.

These objects and features, as well as other incidental ends and advantages, will more fully appear in the progress of the following disclosure, and be pointed out in the appended claim.

In the drawing, to which reference will be made in the specification, similar reference characters have been employed to designate corresponding parts throughout the several views.

FIGURE 1 is a fragmentary view in elevation of an embodiment of the invention, prior to molding.

FIGURE 2 is a fragmentary view in elevation as seen from the right hand portion of FIGURE 1.

FIGURE 3 is a horizontal sectional view as seen from the plane 3-3 in FIGURE 1.

FIGURE 4 is a horizontal sectional view as seen from the plane '44 in FIGURE 2.

FIGURE 5 is a sectional view as seen from the plane 5-5 in FIGURE 2.

FIGURE 6 is a vertical sectional view of a completed fastener showing the metallic core element encased within the synthetic resinous body element.

FIGURE 7 is a similar sectional View as seen from the right hand portion of FIGURE 6.

In accordance with the invention, the device, generally indicated by reference character 10, comprises broadly: a metallic core element 11 and a synthetic resinous body element 12.

The metallic core element 11 is formed from a sheet metal blank 15 by use of progressive extruding metal dies (not shown). As formed, the core elements are permitted to remain initially connected to the blank, as will more fully appear hereinafter. As best seen in FIG- URE 2 in the drawing, the device It) includes an upper "ice frangible shank member 16, the lower end 17 of which is provided with a nicked port-ion to facilitate breakage in the plane of the face of the completed device. The shank member 16 is connected to an upper transverse member 22, in turn connected to an angularly disposed member 24. A lower transverse member is arranged parallel to the upper transverse member 22 and connects with an elongated axially disposed member 26 which forms a reinforcement for the shank portion of the completed device.

The upper transverse member 22 includes an upper surface 28, a lower surface 29 and an arcuate edge surface 30. An elongated slot 31 extends through the plane of the upper transverse member 22 to permit engagement and torque transmission therethrough. Where other tool engaging configirations are desired, the slot 31 may be altered in conformance to such requirement.

The angularly disposed member 24 is interconnected through a bend portion 34, and is bounded by rectilinear side edges 35 and 36, an inwardly disposed surface 37 and an outwardly disposed surface 38'. A stiffening rib 39, best seen in FIGURE 5, is preferably provided to absorb torque, and transmit the same to the shank portion of the device.

The lower transverse member 25 includes an upper surface i2, a lower surface 43, and is interconnected to the angularly disposed member 24 through a bend portion 44.

The axially disposed member 26, as has been mentioned, forms a shank reinforcing member adapted to transmit torque imparted to the upper transverse member 22. It includes a polygonal outer surface 46, a corresponding polygonal inner surface 47, and is bounded by longitudinal edges 48 and 49. A plurality of segmented annular grooves 50 are impressed into the curved plane of the member 26 to provide anchoring means for the synthetic resinous material molded upon the same, and the presence of an elongated opening formed by the edges 43 and 49 permits the flow of synthetic resinous material within the bore 51.

The synthetic resinous body element 12 may be of any standardized outer configuration, and includes a head member and a shank member 56. The head member 55' includes an upper surface 58 having slotted toolengaging means 59 corresponding to the slot 31 in the upper transverse member 22. The tapered outer surface 66 converges in a downward direction toward the shank member 56.

The shank member 56 includes an outer portion 62 having a threaded surface 63 and an inner portion 64 disposed within the axially disposed member 26.

During the process of formation, the metallic core elements are formed continuously upon the blank 15, the blank 15 being severed at convenient intervals corresponding to the number of cavities in the injection mold employed (not shown). The core elements are positioned within the multi-cavity mold in such manner that the upper shank members 16 extend outwardly of the mold, and upon the closing of the mold synthetic resinous material is injected about each of the enclosed core elements. After completion of the molding operation, the shank members 16 extend outwardly of the formed devices it), and may be readily severed therefrom without difficulty. This final operation is preferably performed after the molded devices have been removed from the mold.

By virtue of the interconnected relation of the cores at the time the same are placed in the mold, the necessity of positioning individual formed cores is eliminated, thus materially simplifying the molding process.

By virtue of the configuration of the core element, the

3 invention also lends itself to use with ceramic outer casing elements as compared With synthetic resinous ones. Where ceramics are employed, the molding teei 'que being substantially similar, except that the core elements are permitted to remain attached to the blank during the firing operation so as to facilitate handling.

1 Wish it to he understood that I do not consider the invention limited to the precise details of structure shown and set forth in this specification, for obvious modifi cations will occur to those silled in the art to which the invention pertains.

A composite threaded fastener having a metallic core element and a synthetic resinous body element surrounding said core element, said body element including a head member and an integral threaded shank member ex tending therefrom, said head member having a transverse upper surface with an axially extending tool-engaging slot therein, said core element being of planar int n'al configuration and including a first upper transverse member of generally arcuate configuration positioned adjacent and parallel to said transverse surface, there being a tool-engaging slot extending through said transverse member in alignment with the slot in said head member,

References Cited in the file of this patent UNITED STATES PATENTS 341,413 Fowler May 4, 1386 2,323,216 Goldschmidt June 29, 1943 2,382,245 McCormack Aug. 14-, 1945 2,432,986 Porman Dec. 23, 194-7 2,521,378 Kolessar Sept. 5, 195% 2,899,845 Kiekhaefer June 16, 1959 2,933,066 Gibb Apr. 19, 1962) 2,935,552 Forman May 3, 1960 2,993,950 Forman July 25, 1961 2,999,276 Morin Sept. 12, 1961 FOREIGN PATENTS 53,665 Netherlands Dec. 15, 1942 

